<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <script src="../react18/react.development.js"></script>
    <script src="../react18/react-dom.development.js"></script>
    <script src="../react18/babel.min.js"></script>
</head>
<body>
    <div id="app"></div>
    <script type="text/babel">
        class Child extends React.Component{
            state={
                a:1,
            }
            render(){
                return <h1>hello Child</h1>
            }
        }
        class App extends React.Component{
            render(){
                return <div>
                    <input type="text" ref="iptEle"/>
                    <Child ref="childComp" />
                    <button onClick={this.getValue}>打印输入框的内容</button>
                    </div>
            }
            getValue = ()=>{
                console.log(this);
                console.log(this.refs.iptEle.value)
            }
        }
        
      ReactDOM.createRoot(document.getElementById("app")).render(<App />);
    </script>
</body>
</html>